The present invention relates to a sheet feeding device for feeding a sheet to an image forming section via a feeding route from a storage section, such as a manual-feed tray and a paper cassette storing sheets such as copy paper, and image forming apparatuses such as a copying machine and a printer comprising the sheet feeding device, and more particularly relates to a sheet feeding device and an image forming apparatus comprising a plurality of storage sections.
Image forming apparatus such as copying machines and printers are well-known, and such an apparatus comprises a plurality of storage sections such as paper cassettes storing sheets such as copy paper, and a sheet feeding section (sheet feeding device) for feeding a sheet stored in the storage section to an image forming section via a feeding route, and forms an image on the sheet fed to the image forming section from the sheet feeding section.
In particular, in an image forming apparatus called a mid- or high-speed machine with a high image formation speed, a large-capacity storage section for storing a large amount of paper of frequently used size is mounted and connected as an accessory device.
Moreover, in order to prevent complicated feeding routes for feeding sheets from a plurality of storage sections to the image forming section, the image forming apparatus is designed to simplify the feeding routes by using a common feeding route as much as possible.
By simplifying the feeding routes, it is possible to achieve a small-size image forming apparatus and prevent an increase in the costs required for production, distribution and management, and it is also possible to easily remove a sheet in a feeding route in the event of a malfunction such as a paper jam.
As a conventional image forming apparatus, there is disclosed an apparatus in which a feeding route is shared by providing a paper cassette (storage section) storing paper with a paper transport mechanism for guiding paper fed from another paper cassette to a discharge section of paper fed from the paper cassette (see, for example, Japanese Patent Application Laid-Open No. H1-98529).
Further, there is disclosed an apparatus designed to allow easy removal of a sheet material (sheet) stuck in a transport path (feeding route) by opening the transport path in an interlocked manner with pulling out of a feed cassette (storage section) (see, for example, Japanese Patent Application Laid-Open No. 2002-274675).
In the conventional apparatuses, however, during the formation of an image on a sheet stored in one storage section among a plurality of storage sections, for example, when an operator tries to fill another storage section with sheets, the operator has a problem that the other storage section can not be pulled out because the transport path is opened if the storage section is pulled out, and, if the storage section is pulled out by mistake, a problem such as a transport malfunction will occur.